Are NASA astronauts struck on board a Boeing aircraft? What is this important mission they are a part of?

economictimes.indiatimes.com:

NASA astronauts who are struck on a Boeing Star liner aircraft will return by July 20. They have travelled to the International Space Station (ISS). This aircraft can spend only up to 45 days docked to the ISS. Their lift-off was on June 5. There are two astronauts on board this aircraft.
Sunita Williams and Butch Willmore were scheduled to stay for a week but the stay was extended due to certain helium leaks and thruster problems. NASA is also experimenting with various US private agencies to launch their astronauts so as to cut down their reliance on the Russians. This has been reported by Fox News.

Star Liner Aircraft:

Boeing has said that the helium leak issue has been resolved and the thruster problem too has been stabilized. They will no longer pose a threat for the aircraft to return to earth. One of the thrusters is reported to be offline while 26 others are stable. Four to five thrusters that had shut down earlier are said to be working effectively.

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While a return date has not yet been confirmed, Reuters mentioned that the aircraft will return from the ISS on July 6. After 45 days, post the lift-off, the aircraft can still operate for another 72 days on back up power.

Strategic objectives:

NASA has informed that while all the major issues have been settled, they are using the extra time to clear the path for some critical activities. They are focusing on systems upgrade. NASA seeks to send its